#11 Turn-about compass, 18th century.
German silver turnabout compass (also called turn-in compasses, case 151x29x19mm.
NOTES / REFERENCES
Turn-up COMPASSES, a late Contrivance to save the trouble of changing the Points : The Body is like the common compasses; towards the bottom of the Legs, without side, are added two other Points besides the usual ones; the one carrying a drawing Pen- point the other a Porte Craion; both adjusted so as to turn round, and so be in the way of use, or out of it, as occasion requires.
2. Hambly, Maya; Drawing instruments 1580-1980, p. 82.
3. Instruments of Science: An Historical Encyclopedia edited by Robert Bud, Deborah Jean Warner; p.191.
4. Edmund Stone, Nicolas Bion; The Construction and Principal Uses of Mathematical Instruments, 1723, plate IX. [Internet Archive]
#10 German geological compass, mid 19th century.
Small brass geological compass, base-plate 90x70mm. In German Setzkompass (1), usually mounted on a brass base-plate, with the compass housing measuring 7cm or less in diameter (5). The French and German mining compass, called a sächsische Kompass (5), typically feature a graduation in twice 12 hours and east and west indicators reversed. The compass with 24 hour graduations is called an ungarischen Kompass (5) and were used almost exclusively in Austrian mining practice. Hour graduations on mining compasses, a practice which dates back to the 16th century or earlier, became obsolete in the latter part of the 19th century.
REFERENCES / NOTES
1. Rudolph, Ludwig; Buch der Geologie, Otto Spamer, Leipzig 1861, p. 32, Google Books.
4. Ad. Liebenam; Lehrbuch der Markscheidekunst und praktischen Geometrie, Leipzig 1876, p.71.
5. Beer, August H.; Lehrbuch der Markscheidekunst für Bergschulen und zum Selbstunterrichte, F.A. Credner, Prague, 1856, p.28.
6. Studer, Johann Gotthelf; Beschreibung der verschiedenen Zeichnen- und vorzüglich beim Bergbau nöthigen Vermessungsinstrumente, Dresden 1811. e-rara.ch. See compass on plate 3. http://www.e-rara.ch/zut/content/zoom/617167
7. BRARD, Cyprien Prosper; Élémens pratiques d'exploitation, Levrault, Strasbourg 1829, Google Books, p. 467-470, and illustration on plate XXXII.
#9 German pocket case of drawing instruments, 2nd quarter 19th century.
Unsigned small set. Missing is the ruling pen handle, the adjustment key, and what appears to have been a small compass for which only the small ink-pen attachment survives. In the lid is a clip, possibly to hold a protractor now missing. Case 149x84x20mm.
#8 German drawing set, 4th quarter 18th century.
Unsigned set of German brass drawing instruments in a dark brown leather covered case, gold stamped border decoration, with 2 brass hook-catches, and a red-coloured chamois interior. Contents include 2 ruling pens, a divider with fixed legs, a hair divider, a divider that can be fitted with ink and pencil attachments as well as an extension leg with an adjustable collar.
#7 German drawing set, mid 18th century.
#6 German drawing set, 3rd or 4th quarter 19th century.
German drawing set with an interesting turn about drop bow compass. The case displays the name A.W.C.K. Stolze whom seems to have been the owner, not the maker. The Verbesserter Nullenzirkel or improved drop bow compass features in an article published in the Polytechnisches Journal of 1870. The article does not mention a maker. Case: 211x110x25mm.
#5 German pocket dividers, late 19th or early 20th century.
Kilometerzirkel pocket dividers, 110mm in length. in a cardboard slip case. For use on maps at scale 1:100000. For distances up to 10 kilometres (i.e. 10 on the scale is 10km).
#4 German drawing set, 2nd half 19th century.
#3 German(?) devise for drawing hexagons
Fig. 1: Hand cranked instrument for drawing hexagons. There are 5 discs (the smallest is already in place) for drawing 5 different sizes of hexagons.
Fig. 2: This picture shows the underside of this instrument for drawing hexagons. The ink pen can also be inserted into one of the 6 holes for drawing circles.
#2 Long proportional dividers
Fig. 1: Long proportional dividers (30cm), nickel-silver with steel points. Marked DRGM 437263, German patent dating from 1910, invented by Friedr. August Leiteritz (Warschau). Pivot can be adjusted for ratios ranging from 1:24 to 1:95.
Fig. 2: Two pictures showing the triple-pivot mechanism of the 30cm proportional dividers, unknown maker.
#1 German diagonal scale, first half 19th century.
One side of this brass diagonal scale has 2 scales; one in metres divided into 1cm units, and the other in Rheinlandisches Fuss (31.3853497cm) divided into 6 Zoll, 1 Zoll (inch) is equivalent to 2.61545cm.
The reverse side has a scale in Pariser Fuss (32.4839432cm) divided into 6 pouce, 1 pouce (inch) is equivalent to 2.7069953cm.